Priming mixture



Patented May 28, 1935 PATENT OFFICE PRIMING mxruan Joseph D. McNutt, NewHaven, Coma, assignor to Winchester Repeating Arms Company, New Haven,Conn., a corporation of Maryland I No Drawing. Application November 18,1933,

Serial N0. 698,688

6 Claims.

.This invention relates to priming mixtures for small arms ammunitionand more particularly to a non-mercuric priming mixture.

Heretofore mercury fulminate has been generally used as the initiator inpriming mixtures for small arms ammunition. It possesses many advantagesand it has been difllcult to find other materials to be used in place ofmercury fulminate which wouldproduce as satisfactory results,

' even though considerable efiorthas been made to eliminate mercuryfulminate from priming mixtures. While it possesses certain advantages,it also possesses certain disadvantages. Amalgamation of the cartridgecases caused by the free mercury produced by the decomposition of themercury fulminate when the cartridge is exploded prevents reloading ofcenter fire cartridges. By employing a priming mixture in which nomercury fulminate is present, this' sesses advantages for use in rimfire primers. It

has greater stability on storing and therefore permits the ammunition tobe used and better results obtained after it has been stored for longperiodsof time.

In the present invention I employ an initiator consisting of basic leadtrinitroresorcinol and lead dinitrophenylazide. The leaddinitrophenylazide may be prepared by the method disclosed in my priorPatent No. 1,906,394, granted May 2, 1933. The basic leadtrinitroresorcinolmay be prepared by the method disclosed in the Tausonapplication, Serial No. 690,777, filed September 23, 1933.

I am aware that normal lead trinitroresorcinol has been proposed for useas an'ingredient of priming mixtures for small arms ammunition. So faras I know, basic lead trinitroresorcinol has not been used in primingmixtures for small arms ammunition because of its relatively lowsensitivity. It is, of course, less hazardous to manufacture basic leadtrinitroresorcinol than normal lead trinitroresorcinol because of itslower sensitivlty;

I have found that basic lead trinitroresorcinol may be used incombination with lead dinitrophenylazide as the initiator of a primingmixture, in certain proportions, without materially impairing thesensitivity of the lead dinitrophenylazide. At the same time, itproduces an improved priming mixture because of the greater density ofbasic lead trinitroresorcinol. The density of lead dinitrophenylazide isso low that dimculties in loading the priming mixture into primer cupsor cartridge cases would be encountered if it were used alone as theinitiator. By mixing it in certain proportions with' basic leadtrinitroresorcinol a more workable density is obtained and at the sametime thesensitivity of the priming mixture approximates the sensitivitythat would result if lead dinitrophenylazide were used alone. I

In carrying out my invention the combination 10. of initiators set forthabove may be used with the common oxidizers, fuels and abrasives. Asexamples of priming mixtures which I have found satisfactory I mayprepare a priming mixture for rim fire ammunition by mixing the folllowing ingredients in substantially the following proportions:

' Percent Basic-lead trinitroresorcinol 2'7 Lead dinitrophenylazide 13Double salt of barium and potassium nitrate" Antimony sulphide e 7Ground glass 23 Likewise, a center fire mixture may be pre- Double saltof barium and potassium nitrate" 40 30 A imony sulphide 23 Calciumsilir'ide 7 The proportions of these ingredients may, of course, bevaried depending upon the commercial strength of the ingredients and tomeet the requirements of various uses of the mixtures. Likewise, knownequivalents may be substitutedfor the oxygen supplying elements andfuels without departing from the spirit of the invention. As an 40example, barium nitrate may be substituted for the double salt of bariumand potassium nitrate given in the formula, the quantity of bariumnitrate to be employed varying slightly from the quantity of the doublesalt of barium and potassium nitrate given above to obtain substantiallythe same qualities in the resulting mixtures.

The rim fire mixture is prepared in the usual way, poured intoindividual pellets of the proper size for the individual charges bymeans of a charge plate in the usual manner and then translferred toempty rim fire cartridge shells. The priming mixture is then forced todistribute itself in the hollow rim of the cartridge shell by spinningthe shell in the customary machine.

the priming mixture set forth above, the ingredients are firstthoroughly and homogeneously mixed. The mixture is then poured intoindividual pellets of the proper size for the individual charges in thecustomary way by means of a charge plate provided with perforationsadapted to mold pellets of the proper size. These pellets are thenloaded into primer cups in the usual way and the primer cups thenassembled in. the cartridge cases.

I claim:

1. A priming mixture comprising basic lead trinitroresorcinol and leaddinitrophenylazide.

2. A priming mixture comprising basic lead trinitroresorcinol, leaddinitrophenylazide and the double salt of barium and potassium nitrate.

3. A priming mixture comprising basic lead trinitroresorcinol, leaddinitrophenylazide, the

double salt of barium and potassium nitrate and antimony sulphide.

4. A priming mixture comprising basic lead trinitroresorcinol, leaddinitrophenylazide, the double salt of barium and potassium nitrate,antimony sulphide and calcium silicide.

5. A priming mixture comprising basic lead trinitroresorcinolsubstantially 27 percent, lead dinitrophenylazide substantially I 13percent, double salt of barium and potassium nitrate substantially 30percent, antimony sulphide substantially '7 percent and ground glasssubstantially 23 percent.

6. A priming mixture comprising basic lead trinitroresorcinolsubstantially 22 percent, lead dinitrophenylazide substantially 8percent, double salt of barium and potassium nitrate substantially 40percent, antimony sulphide substantially 23 percent and calcium silicidesubstantially 7 percent.

JOSEPH D. McNU'I'I.

